1. Field of the Invention
The present invention relates to wall systems, and in particular, to modular wall systems made of a plurality of interconnecting, wall components.
2. Related Art
As the demand for electrical power increases around the world, the development and use of nuclear reactors also increases. Accordingly, workers at such nuclear power plants have a great need for portable wall systems that prevent or minimize radiation emanating from a nuclear reactor itself and/or from activation products resulting from reactor operation because the workers often must go into areas of high radiation to perform required maintenance, inspections or repairs. Workers use such shielding wall systems as a means for protecting a designated work area within a nuclear power plant in order for the workers to work within the protected or shielded area without the worry of being exposed to high levels of radiation. In addition, federally required inspections of nuclear power plants necessitate open access to critical areas within the plant. Therefore, there is a need for a shielding system that is easily portable from one location to another while shielding persons within the protected area from unwanted radiation.
Early prior art shielding systems included lead sheets and concrete blocks, but neither of these were easily portable from one location to another. As a result, several patents were issued in attempts to solve the non-portability of these prior art systems. In U.S. Pat. No. 4,090,087 to Weissenfluh, a radiation shield is disclosed having a bag filled with a liquid radiation attenuating material suspended from a mobile carrier. Although an arguable improvement over the early prior art, there are disadvantages with the ""087 system. First, the system cannot fully protect an individual working behind the shield because the bag does not provide complete coverage. There are open areas on all sides of the bag between the mobile carrier and the bag as well as between the ground and the bag. Therefore, unwanted radiation will stream around the shield and compromise the area sought to be protected. The system continues in stating that the filler liquid can be any hydrogenous material which may have a boron compound as a neutron absorber. Therefore, if there is a shortage of such filler material, repairs, inspections, or other work may halt until such filler material is found and brought to the area. Third; the bags are hung from the mobile carrier, as shown in FIG. 11. Thus, the heavy weight of the filler material may compromise the hooks or fasteners holding the bag in place. If the hooks happen to fail, the bag would fall to the ground, perhaps even burst open.
In U.S. Pat. No. 4,360,736 to Weissenfluh, a radiation shield is disclosed which improves upon the shielding system of the ""087 system. Specifically, an improved bag is disclosed which has a means for connecting opposing walls of the bag, thereby ensuring a uniform thickness of the bag throughout its length when filled with a radiation attenuating liquid and hung on a mobile carrier. Despite this improvement to the bag, the radiation shielding system has the same disadvantages as described with the ""087 system above.
In U.S. Pat. No. 4,362,948 to Weissenfluh, a radiation shield is disclosed being a freestanding container of a uniform thickness which is adapted to be used only with a radiation attenuating liquid. This shielding systems solves some of the problems with the prior ""087 and ""736 systems; however, it too has several disadvantages. First, the same problem exists in terms of having to use a radiation attenuating liquid. Second, the container has a fixed U-shape which cannot be altered according to the specific needs of the location sought to be protected. That is, if the target work area sought to be protected is in close proximity to walls, corners, stationary equipment, and the like, the pre-defined U-shape of the container may not work or fit within the confines of the target work area. Therefore, the ""948 shielding system cannot be used.
In U.S. Pat. No. 4,504,739 to Weissenfluh, a method is disclosed for filling and emptying the shield system of the ""948 patent. This method includes the introduction and emptying of both a gas and a radiation attenuating liquid to the container. Therefore, the same problem exists as with the other patented shielding systems described above.
Subsequent to these prior art patents, other commercially available shielding systems have been developed that use water as a filler material. However, as with the prior patented shielding systems, these conventional shielding systems all have a pre-defined shape such that each shape is targeted for a specific application. For example, there are hanging shields that operate as the container or bag of the ""087 and ""736 systems; there are U-shaped shields that operate as the free-standing container of ""948 and ""739 systems; and there are special form bags that conform to the exterior shape of a component piece of equipment, e.g., a section or intersection of pipes, and are intended to wrap and surround the target pipe or equipment.
The disadvantages with all of these prior art shield systems is that none of them are modular such that two or more components can be interconnected to form a unique shaped wall shielding system. By having predefined shapes, the use of the prior art shielding systems is limited. Therefore, there is a need for a portable and modular shielding system having component parts that interconnect to form a shielding wall of varying shapes and sizes.
Another disadvantage with the prior art shield systems is that there is no mechanism for interconnecting two or more shields while maintaining the shielding properties of the shields at the point of connection. For example, when placing two U-shaped shields next to each other in an attempt to protect a larger area, radiation may enter the protected area at the joint of the two adjacent shields. This is true whether the two shields overlapped each other (one placed in front of the other) or not. Therefore, there is a need for a portable and modular shielding system wherein two adjacent component shields maintain the integrity of the shield at their joint and prevent the protected area from seeing increased radiation levels.
Another prior art shielding system is shown in FIGS. 1(A), (B) and 2. In this system, a prior art shield component 100 is designed having a main container 112 with a first end 102 and a second end 104. She first end 102 is a receiving end and the second end 104 is a locking end. Specifically, the second end 104 has a cross-sectional shape that is generally circular wherein the diameter of the second end 104 is equal to the width or thickness of the main container 112. The first end 102 is concave in shape having a diameter and radius and is adapted to correspond to the generally circular shape of the cross section of the second end 104, such that the radius of the first end 102 is equal to the radius of the second end 104. In addition, the prior art shield component 100 is hollow so that it can be filled with any radiation attenuating material, e.g., water. Filling and draining of this prior art system is accomplished through an open port at the top of the shield section, making this an open system.
Using two or more prior art shield components 100, a user can build a prior art shielding wall 200 as shown in FIG. 2. For example, a first shield component 202, having a first (or receiving) end 206 and a second (or locking) end 208, is placed adjacent to a second shield component 204, also having a first (or receiving) end 210 and a second (or locking) end 212. As shown, the locking end 208 of the first shield component 202 is placed within the receiving end 210 of the second shield component 204, thereby creating a conventional xe2x80x9cball and socketxe2x80x9d joint. Once in the proper position, the first shield component 202 can be secured to the second shield component 204 by conventional means.
The main disadvantage with the prior art shield components 100 and a resulting prior art shielding wall 200 is readily apparent at the joint 216 of the first shield component 202 and the second shield component 204. As the first shield component 202 rotates in relation to the second shield component 204 (that is, as the locking end 208 of the first shield component 202 rotates within the receiving end 210 of the second shield component 204), a gap 214 is created thereby compromising the integrity of the shielding wall 200 at that location. That is, at the gap 214 in the joint 216, there is less shielding protection for persons in the protected area because the level of protection is less than the width, or thickness, of each shield component 202, 204.
Therefore, there is still a need for a modular wall component that provides the same level of protection against radiation at its joints of two adjacent components as it does along the length of each such component.
The present invention is a modular and portable shielding system that solves the problems of the prior art shielding systems. A portable and modular shielding system is disclosed having various modular wall components that can be interconnected to form a custom designed shielding wall configuration, wherein the resulting wall provides shielding from radiation at its joints of two adjacent modular wall components as well as along its entire length.
There are four types of modular wall components in the present invention. The principal modular wall component is a main container being generally rectangular in shape and having a connector container, being an elongated cylinder, e.g., a tube, having a cross section that is generally circular in shape, integrally connected to the second end of the main container, thereby making it a locking end. The first end of the main container is concave in shape and adapted to correspond to the generally circular shape of the connector container, thereby making it a receiving end for the locking end of an adjacent modular wall component. A second modular wall component is a main container having a connector container on each of its ends. A third modular wall component is a main container wherein each of its ends is a receiving end for a connector container of an adjacent modular wall component. A fourth modular wall component is a main container wherein its first end is a receiving end for a connector container of an adjacent modular wall component and its second end is a straight end such that it can abut up to an existing flat wall or surface.
The modular wall components of the present invention may be hollow containers adapted to receive a filler material, e.g., water, or may be solid, e.g., concrete. Furthermore, one or more internal supports may be used to strengthen and ensure the shape of the modular wall components, as well as, one or more leg supports may be used to support a modular wall component in a free standing and upright position on a base surface, e.g., the ground.
In operation, a shielding wall is designed and built by interconnecting two modular wall components. That is, a connector container of a first modular wall component is fit and secured into a receiving end of a second modular wall component. This interconnection of two adjacent modular wall components is similar to a xe2x80x9cball and socketxe2x80x9d joint. Therefore, an advantage of the present invention is that a custom-designed shielding wall may be built according to the restrictions of the area sought to be protectedxe2x80x94the target area. The design simply uses the modular wall components needed for the specific target area. In addition, because a connector container can rotate within a receiving end of another modular wall component, two adjacent modular wall components can be interconnected at any angle up to 90 degrees in either direction. A mechanical fastener also can be used to further secure the two adjacent modular wall components.
Another advantage of the present shielding system is that the resulting shielding wall prevents radiation streaming at its joints. There are no open seams in the resulting shielding wall which would allow the unwanted radiation to penetrate. Also, the shielding wall has a uniform thickness along its entire length, even at its joints of two adjacent modular wall components. Therefore, the modular wall components of the present system provide a better shielded target area for workers.
Another advantage of the present invention is that a means to fill and drain the modular wall components may be positioned on the front face of the modular wall components. This allows for a first modular wall component to be stacked on top of a second modular wall component wherein the fill and drain means of the two modular wall components are connected.